Methods of forming woven stretchable fabrics



1966 N. SELTZER 3,227,511

METHODS OF FORMING WOVEN STRETCHABLE FABRICS 2 Sheets-Sheet 1 Original Filed Aug. 2, 1961 INVENTORI NORMAN L. SELTZER.

BYW

ATTORNEY N. L. SELTZER 3,227,511 METHODS OF FORMING WOVEN STRETCHABLE FABRICS Jan. 4, 1966 2 Sheets-Sheet 2 Original Filed Aug. 2, 1961 F -12 BYWM g M Mm ATTORNEYS NORMAN L. SELTZER,

lNVENTOR United States Patent 3,227,511 METHODS OF FORMING WOVEN STRETCHABLE FABRICS Norman L. Seltzer, Princeton, N.J., assignor to The Kendall Company, Boston, Mass., a corporation of Massachusetts Original application Aug. 2, 1961, Ser. No. 128,810 now Patent No. 3,145,132, dated Aug. 18, 1964. Divided and this application May 3, 1963, Ser. No. 277,884

9 Claims. (Cl. 8116.3)

This invention relates generally to woven stretchable fabrics which are particularly adapted to be treated with a stabilizing material in the nature of an impregnation or coating, with the resulting fabrics having many enhanced and novel characteristics over prior art fabrics. This application is a divisional application of application Serial Number 128,810 (now Patent No. 3,145,132), entitled Woven Stretch-able Fabrics and Methods of Forming the Same, filed August 2, 1961.

There are two general types of stabilizing treatments that are applicable to this invention. In the first, the fabric is impregnated with a relatively minor amount of material such as resins or other fabric modifiers consisting essentially of thermosetting resins and cross-linking reactants to impart wrinkle-resistance, crease recoverability, dimensional stability, and quick-drying properties to textiles such as apparel fabrics. Such finishes, in which the outward physical appearance of the fabricis essentially unaltered, have attained considerable commercial success as wash and wear finishes.

The second type of stabilizing treatment involves the use of a relatively large amount of resin to coat or cover the fabric, frequently obscuring the Weave, so that the fabric serves as a matrix or base for a coating of a generally elastomeric or thermoplastic resin. Such applications are familiar as upholstery material, luggage coverage, and many other uses.

Prior art fabrics utilizing either type of stabilizing treatment suffer from at least two drawbacks. Either type of application results in a decrease in the tear strength of the fabric and either application decreases the inherent toughness of the fabric. In the case of Wash and wear type finishes, these drawbacks are directly traceable to the stabilization treatment immobilizing the yarns to a large degree and reducing their natural resiliency, which prevents the yarns from giving under certain stress conditions, particularly large or exaggerated stresses. The decrease in these qualities has the serious consequence of definitely limiting the field of utility of these two types of treatment. The decreased tear strength and toughness resulting from such treatment frequently necessitates the use of a stronger initial base fabric than is really needed i.e., in order to meet a certain commercial standard of tear strength and toughness after treatment, the hitherto inevitable loss of a part of those valuable properties has been compensated for by 'overdesigning the base fabricthat is, by selecting a base fabric with tear strength and toughness substantially in excess of the tear strength and toughness expected after conventional treatment. This is obviously an undesirable and uneconomical expedient.

In prior art treatment of the first type, for example Where a thermosetting resin is used, the thermosetting resin applied is generally of a non-extensible nature, and it is applied to a woven fabric with very modest extensibility. The application of a stress to such a treated fabric, therefore, means a decreased tear strength, as

well as lack of recovery, because there is no provision in the fabric for any appreciable degree of coaction between fabric yarns and resins.

3,227,511 Patented Jan. 4, 1966 ice In prior art treatment of the second type, a thermoplastic coating is applied which is potentially capable of considerably greater elongation than the elongation of commercial base fabrics. Stress or deformation of such coated fabrics results in the pulling or tearing away of the elongatable coating from the yarns, with loss of product utility. Again, there is no provision in prior art woven base fabrics for coaction between coating and base fabric, so that coating and fabric can work together as a unitary structure.

I am aware that efforts have been made to overcome these objections by the use of stretchable base fabrics such as knitted goods, or crepe weaves. However, knitted fabrics are notoriously unstable, having a tendency to stretch almost without restriction. For example, in finishing knitted goods, a pull on the fabric in the direction of feed results in difficul-ty in controlling the stretch thereof as well as causing a narrowing or pull in of the width there-of. Therefore, the processing of suitable knitted fabrics in resin application is normally difficult or impossible. Thus, the problems attendant to controlling the stretchability of knitted fabrics have limited the market and use thereof. Furthermore, the fact that suitable knitted fabrics, per yard, are generally more, expensive than woven fabrics has further contributed to the limited use thereof. Crepe fabrics have likewise a definite instability, and additionally have a pebbled surface which demands repeated coatings before a smooth finish is obtained.

Moreover, in treatments of the first or wash and wear type, no treatment can make the fabric appear otherwise than'as a knitted fabric or a crepe fabric, which limits the use of these materials. Furthermore, in the case of knitted fabrics provided with thermoplastic coatings, the surface of the coating does not normally attain the desired smoothness, but continues to exhibit a somewhat roughened or non-uniformappearance.

It is the essence of this invention that I have found that it is possible to so design, produce, and finish a woven base fabric as 'to enable it to coact with a stabilizing treatment of either the first or second type, whereby the defects of prior art fabrics are overcome. Not only do the treated fabrics of myinvention possess an enhanced toughnessand tear strength over similarly treated prior art woven fabrics, but they also show both an increased degree of recovery of the original state, and a definitely increased speed of such recovery upon the release of applied stress. This is particularly important in the apparel field, where garments may be fashioned with the desirable characteristics of wash and wear properties combined with an easy yield to and quick recovery from stretching, bending, and deformation in general. These results, so far as I am aware, are not attainable in prior art fabrics.

It is a primary object of this invention to provide a woven base fabric, having considerable stretchability, and' which is particularly adapted to be impregnated or coated with stabilizing materials of the types described, and wherein the basefabrics and stabilizing materials coact and Work together as a unitary structure to provide stabilized stretchable fabrics of enhanced toughness and tear strength, and wherein the fabrics exhibit both an increased degree of recoverability, as well as speed of recoverability following any stretching thereof.

It is a more specific object as one aspect ofthis invention, to provide woven wash and wear type fabrics which, when being used in the normal dry state, have for the first time the important dry state characteristics of a wide range of stretchability, as well as enhanced tear strength, toughhness, and quick recoverability from stretching, even at high elongation, to thus permit such fabrics to be readily utilized in the apparel field, wherein these properties contribute materially to the comfort, wearability, and life of the garment.

Briefly, the foregoing objects are accomplished by suitably interweaving normally non-stretchable warp and weft yarns formed of staple fibers, such as cotton, to provide a woven fabric of the desired dimensions. This woven fabric is then suitably treated, as by a strong contracting and swelling agent, to reduce the dimensions of the fabric in at least one direction while simultaneously imparting crimp to the yarns in this direction, thus making the fabric stretchable. The fabric is then treated with a stabilizing material while in this contracted condition to resiliently maintain the yarns in their crimped condition, thus imparting quick recoverability to the fabric to return the fabric to unstretched condition following any stretching thereof.

The type of stretchable base fabric with which the present invention is primarily concerned is one in which the mesh or distance between the interwoven yarns is relatively small and the cover factor is at least eight or more. Also, the yarns utilized are preferably made from cellulosic and water-swellable fibers and of a nonstretchable nature, such as cotton, rayon, or blends or mixtures thereof and are within the range of from 12/ to 50/1. Further, the yarns which extend in the stretchable direction have a twist multiple within the range of from 3.5 to 7. The sum of warp and filling yarns per inch may vary within the range of from 60 to 160 and the base fabric may be stretched within the range of from 15 to 50 percent, with a stretch of approximately 30 percent being preferred.

The term non-stretchable yarns, as used herein, is directed to those yarns such as cotton and rayon which are normally non-heat-shrinkable and which inherently have little stretchability and to distinguish these yarns from those yarns of a true stretchable nature, such as texturized nylon stretchable yarns, rubber, or the like.

The term wash and wear finish or treatment, as used herein, is to define those stabilizing materials consisting essentially of thermosetting resins and/or cross-linking reactants which impart the desired characteristics to the fabric, with the outward physical appearance of the fabric being essentially unaltered.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which- FIGURE 1 is a greatly enlarged isometric view of a small portion of one type of woven fabric which may be rendered stretchable and then have a wash and wear finish applied, illustrating the appearance of the interwoven warp and weft yarns before the fabric is reduced 1n s1ze;

FIGURE 2 is an enlarged vertical sectional view taken substantially along the line 22 in FIGURE 1 and illustrating the spaced apart relationship of one group of yarns and the manner in which the yarns of the other group are sinously interwoven therewith;

FIGURE 3 is an isometric view of the fabric shown in FIGURE 1 and illustrating its appearance after the dimensions thereof have been reduced in one direction;

FIGURE 4 is an enlarged vertical sectional View taken substantially along the line 44 in FIGURE 3 and illustrating the manner in which the yarns of one group are drawn closer together and the sinuosity of the yarns in the other group is increased;

FIGURE 5 is a view similar to FIGURE 4 with the speckles on the yarns representing a relatively light-weight stabilizing treatment of thermosetting material applied thereto to resiliently maintain the fabric in the unstretched condition;

FIGURE 6 is a view similar to FIGURE 5 but showing the relationship of the yarns when the thermosetting treated fabric is stretched to substantially its outermost limit;

FIGURE 9 is a view similar to FIGURE 7, but illustrating its appearance after the dimensions thereof have been reduced in one direction;

FIGURE 10 is an enlarged vertical sectional view taken substantially along the line 1i31i) in FIGURE 9 and illustrating the manner in which the yarns of one group are drawn closer together and the sinuosity of the yarns in the other group is increased;

FIGURE 11 is a view similar to FIGURE 10 and illustrating a relatively heavy coating or film of thermoplastic resin such as vinyl applied to one face of the fabric and the coating acting to resiliently maintain the fabric in unstretched condition; and

FIGURE 12 is a view similar to FIGURE 11, but showing the relationship of the yarns when the fabric is stretched to substantially its outermost limit.

Stretchable woven fabrics of varying constructions may be produced in accordance with the present invention, with the desired end uses of the fabrics determining the size and manner in which the yarns are interwoven. Generally, the fabric is woven with a somewhat open-mesh to provide sufficient space for at least one group of yarns to be moved closer together to effect a reduction of the dimension of the fabric in this direction. However, the yarns do not have to be spaced so far apart that the fabric appears to be open mesh when viewed with the unaided eye. The openness of the weave should be sufficient, however, to prevent an undue crowding together of the yarns as the fabric is contracted, thereby preventing buckling, wrinkling or the like of the type which is characteristic of crepe fabrics.

While the amount of stretchability of the fabric will in large part be controlled by the yarn spacing and the ability of at least one of the groups of yarns to contract, the yarn size, the number of yarns per inch and the weave of the fabric also exert an influence on the stretchability thereof. The woven stretchable fabric of the present invention is not substantially increased in thickness by the contraction thereof and has no visible crinkles or wrinkles so that the resulting fabric may have a wash and wear finish applied thereto or be coated with thermoplastic type resins by any of the known methods.

The stretchable wash and wear fabrics may be used to make stretchable fitted sheets for beds and cribs, mattress ticking, shirts, dresses, uniforms, pajamas, shorts, or heavier clothing, such as blue jeans and the like and outerwear, such as raincoats, jackets and the like. The stretchable fabrics which are coated with thermoplastic material may be used as household and automotive upholstery material, waterproof articles of clothing, shoes, luggage, wall coverings, boat covers, girdles, brassieres, and the like wherever recoverability and conformability are desired.

A general description of the preferred method of producing the stretchable wash and wear type fabric and the coated type fabric will be given first, and then specific examples will be set forth. It is believed that with the general description and specific examples, those skilled in the art will be able to readily adapt the teachings of the present invention to a wide range of stretchable fabrics without departing from the spirit of the invention.

In forming the base fabric, groups of warp and filling yarns may be interwoven in a plain weave, a sateen weave or any other desired weave as long as the spacing between 5. the yarns is sufiicient to allow the fabric to be reduced in at least one dimension following the weaving operation.

After the fabric is woven, its dimension is reduced in at least one direction by any suitable means, such asby wetting the fabric in the presence of a strong swelling and contracting agent, such as caustic soda, to contract the fabric and impart increased sinuosity and crimp to. the yarns. Also, the fabric may be reduced by mechanical means in which at least one group of the yarns is moved closer together to impart crimp to the yarns running in the opposite direction.

While the fabric is in at least partially reduced or contracted condition, the desired stabilizing material is applied thereto to resiliently maintain the fabric in its contracted condition. The thus treated fabric may then be stretched or elongated, in the direction in which it has previously been contracted, within the range of from to 50 percent, with the stabilizing material serving to quickly return the fabric to its contracted relaxed condition more quickly following the release of stresses thereon.

There are a number of dilferent types of wash and wear finishes available which may be utilized to re.- siliently maintain the stretchable fabric in its relaxed contracted condition and the type of finish used will depend, to a large degree, upon the end use of the stretchable fabric. These wash and wear finishes, as stated earlier, consist essentially of thermosetting resins and/or crosslinking reactants and are normally applied to the fabric by impregnation without essentially altering the outward physical appearance of the fabric. Suitable thermosetting resins for this purpose are triazone, urea formaldehyde, melamine formaldehyde, etc. Examples of suitable cross-linking reactants are epichlorohydrin, formaldehyde, and divinyl sulfone.

For obtaining a relatively heavy coating on the fabric, resins such as a thermoplastic type vinyl or polyurethane may be applied to one face of the fabric to provide a stretchable water repellant or impervious material in which the base fabric provides a stretchable carrier or support for the relatively heavy coating.

In testing both types of treated fabrics produced in accordance with the present invention, it has been generally found that the amount the fabric recovers after elongation, particularly high elongation, is increased. Also, when the stretchable fabric is provided with a wash and wear finish of the first type, the tear strength is unexpectedly higher than the tear strength of a similarly treated non-stretchable fabric. Furthermore, when the stretchable fabric is treated with a wash and wear finish or coated with thermoplastic material, the snapback or rate of recoverability of the fabric is greater than the rate of recoverability of the untreated fabric.

The yarns which extend in the non-stretchable direction of the fabric are preferably formed of twisted staple fibers which are generally given a normal amount of twist, and the yarns which extend in the stretchable direction of the fabric may be twisted with a twist multiple of from 3.5 to 7, which is calculated in the usual manner by dividing the square root of the yarn size into the turns per inch of the yarn. Since the amount of twist in the yarns will affect, to some extent, the surface smoothness 'of the stretchable fabric, it is preferred that the yarns which extend in the stretchable direction have a twist multiple no greater than seven to avoid the obtaining of crepe yarns which result in a pebbled surface on the fabric.

In order to more clearly illustrate the invention, the following examples disclose specific stretchable fabrics which have been given both types of stabilizing treatmeans. Also, the results of various tests conducted on these fabrics are set forth in the examples. It is to be understood that the following examples are merely given as illustrations which may be followed to produce certain types of Woven stretchable fabrics and that other types of stretchable fabrics may be produced by varying 6 the constructions thereof or the type of stabilizing materials applied, as desired.

WASH AND WEAR Referring to FIGURES 1 through 6, there is shown a woven fabric of the type which is suitably treated with a thermosetting resin or cross-linking reactant after it has been woven and then rendered stretchable in one direction. In weaving the fabric shown in FIGURES l and 2, a plain weave is utilized to interweave the warp yarns, indicated at 10, and the filling or weft yarns, indicated at 11. The warp yarns 10 are formed of cotton staple fibers which are processed to produce a yarn having a cotton count size of 31.5/1 and a normal twist multiple of 4.2. In weaving the grey fabric shown in FIGURE 1, 92 warp yarns per inch are utilized and the fabric is woven 50 inches wide.

The filling yarns 11 are formed of cotton stapie fibers which are processed to produce a yarn having a cotton count size of 30/ 1 and a twist multiple of 6.5. The grey fabric shown in FIGURE 1 contains 60 filling yarns per inch. The cover factor of this grey fabric is calculated in the usual manner by dividing the square root of the yarn size into the number of yarns per inch in the fabric. Thus, the warpwise cover factor is 16.7 and the fillingwise cover factor is 10.9.

The grey fabric shown in FIGURE 1 is then subjected to a causticizing, scouring and bleaching process which results in a fillingwise contraction and reduction of the fabric to produce a stretchable fabric such as that illustrated in FIGURE 3. Furthermore, the caustic treatment causes the yarns to shorten, thereby increasing the twist or turns per inch. It will be noted as shown in FIGURES 3 and 4 that the sinuosity of the filling yarns 11 has been increased to thus impart considerable crimp to the yarns. Also, the causticizing process has caused the filling yarns to draw the warp yarns 1t) closer together. The processed fabric has 105 warp yarns per inch and 58 filling yarns per inch with a warpwise cover factor of 18.9 and a fillingwise cover factor of 10.6.

The process for causticizing, scouring and bleaching the fabric is preferably continuous with the fabric being pulled forward warpwise to apply tension thereto, while being untensioned or relaxed fillingwise, which further aids in increasing the sinuosity of the filling yarns. The process includes subjecting the grey fabric to an openwidth saturation of from 100 to 110 pick-up per cent based on dry weight of the fabric in a sodium hydroxide (NaOH) concentration of 26 Tw. at a temperature of from 95 to 105 degrees F. The fabric is then steamed in a I tube for 30 minutes at a temperature of from 200 to 220 degrees F., washed and then continuously subjected to the conventional scouring and bleaching process. The causticized, scoured and bleached fabric is finished 43 inches wide and is stretchable in a fillingwise direction.

The stretchable fabric (FIGURES 3 and 4) is then further treated by applying blueing and optical brighteners, drying, padding on a low-chlorine-retentive triazone type thermosetting resin containing approximately eight percent active resin in the bath, appropriate metal salt catalysts, softeners and han drbuilders, 68 percent of which are picked up at degrees F. The thermosetting resin treated fabric is then dried on a tenter frame at 275 degrees F., calendered and heat-cured at 325 degrees F. for seconds, and wound into suitable bolts or rolls with a fabric width of 44 inches.

Tests have been conducted onthe causticized, scoured and bleached stretchable fabric before the resin finish is applied thereto and tests have also been conducted on the resin finished fabric.

In testing the stretchable fabric shown in FIGURES 3 and 4, prior to its being subjected to a resin treatment, it has been found that it will stretch 30 percent in a filling wise direction at break. Also, it will recover a relatively low percentage of the amount stretched, particularly when 7 elongated or stretched near its upper limit. Thus, the amount of stretch recovery of the causticized, scoured and bleached fabric is relatively low.

The following chart indicates the percentages of stretch of the base fabric when various forces are applied in a fillingwise direction:

STRETCH IN RESPONSE TO FORCE Force, lb./in.: Percent stretch The stretch recovery of the causticized, scoured and bleached fabric has been calculated by stretching fabirc strips in a fillingwise direction, new ones each time, to various distances ranging from 10 to 90 percent of their total elongation at break, relaxing the strip for two minutes and then determining the percentage of stretch recovered during this period. This test was conducted on an Instron Tester with the C cell set at 20 pound load, the cross head speed being 5/minute, the chart speed being In testing the stretchable thermosetting resin finished fabric (FIGURES 5 and 6), it has been found that it will stretch 24 percent in a fillingwise direction at break, and that it will recover a relatively high percentage of the amount stretched. For example, the following chart indicates the percentage of stretch of the fabric when various forces are applied in a fillingwise direction:

STRETCH IN RESPONSE TO FORCE Force, lb./ in. Percent stretch The results of the stretch recovery test of the stretchable resin finished fabric are listed in the chart below:

Stretch Recovery Inches Percent of Inches re- Percent of per 5 stretch covered stretch recovered A comparison of the stretch recovery characteristics of the stretchable resin finished fabric with those of the stretchable fabric before the resin finish is applied thereto reveals that the resin finished fabric quickly recovers a greater percent. Also, the percentage of filling stretch at break compared to 24 percent) is not greatly reduced, and the ability to stretch in response to given forces is not substantially reduced by the resin finish, particularly when the higher forces are applied.

The filling toughness of the resin finished stretchable fabric has also been determined by multiplying the fillingwise tensile strength (26.9 lbs.) by the percent of filling stretch at break (24), and then dividing this product by two. This calculation results in a filling toughness of 323 in the resin finished stretchable fabric.

The filling toughness of a standard prior art resin treated non-stretchable wash and wear type broadcloth fabric having the same construction as the stretchable resin treated fabric of the present invention has been determined to be 172 based on a fillingwise tensile strength of 30.8 and a filling stretch at break of 11.2.

In comparing the filling toughness figures, it is apparent that the stretchable Wash and wear fabric of the present invention has almost twice as much toughness. This contributes materially to increasing the life and wearabillty of the fabric.

The tear strength of the aforementioned prior art wash and Wear fabric has been found to be 3.03 lbs. in a warpwise direction and 1.53 lbs. in a fillingwise direction. The tear strength of the resin treated stretchable fabric of the present invention is 3.42 lbs. in a warpwise direction and 2.59 lbs. in a fillingwise direction. It should be noted that the tear strength in both directions has been considerably increased, with the fillingwise tear strength exhibiting a percent increase.

Modulus of elasticity tests have also been conducted on these two fabrics. The prior art Wash and wear fabric had a modulus of 4.48 as compared to 2.96 for the stretchable fabric of this invention. The substantially lower modulus figure of the instant invention is thus indicative of a much greater compliance of the fabric to yielding under stress conditions.

Although the conventional Wash and wear fabric and the stretchable wash and wear fabric of the present invention have substantially the same appearance to the eye, the fabric of the present invention is much more desirable because of its ability to readily stretch and yield, its ability to recover quickly, its markedly increased tear strength and its greatly enhanced filling toughness.

COATED FABRIC Referring to FIGURES 7 through 12, there is shown a woven fabric of the type which is adapted to be coated With a thermoplastic resin after it has been rendered stretchable in one direction. In weaving the fabric shown in FIGURES 7 and 8, a special type of open Weave is utilized to interweave the warp yarns indicated at 20, and the filling yarns, indicated at 21. The weave pattern is shown in the following draft form diagram, in which the horizontal rows of squares represent picks of filling yarns 21 and the vertical rows represent the manipulation of warp yarns 20.

The warp yarns 20 are formed of cotton staple fibers whichare processed to produce a yarn having a cotton count of 22/1 and a normal twist multiple of 4.2. In

. 9 weaving the grey fabric shown in FIGURES 7 and 8, 80 warp yarns per inch are utilized and the fabric is woven 76 inches wide. The filling yarns 21 are formed of cotton staple fibers which are processed to produce a yarn having'a cotton count size of 30/ 1 and a twist multiple of 6.5, with the fabric having 60 filling yarns per inch. The cover factor is 17 in the warpwise direction and 10.9 in the fillingwise direction.

The grey fabric shown in FIGURES 7 and 8 is then subjected to a continuous causticizing and bleaching process similar to that previously described, which results in a fillingwise reduction of the fabric to render the fabric stretchable fillingwise, as illustrated in FIGURES 9 and The fabric is finished 57 /2 inches Wide with 2.01 running yards per pound. The fabric contains 100 warp yarns per inch and 64 filling yarns per inch, with a warp wise cover factor of 21.3 and a fillingwise cover factor of 11.7.

The stretchable fabric is then given a thermoplastic coating of vinyl resin on one face thereof (FIGURES 11 and 12) which reduces the running yards per pound of the fabric to 0.52. The coating, indicated at C, is then cured or dried and the stretchable coated fabric is wound into suitable bolts or rolls.

In testing the stretchable fabric prior to being coated, it has been found that it will stretch 39.6 percent in a filling- Wise direction at break, stretches varying amounts in response to various amounts of force being applied thereto, and will quickly recover only a relatively low percentage ofthe amount stretched, particularly when elongated or stretched near its upper limit.

The following chart is representative of the percentages of stretch of the uncoated fabric when various forces are applied in a fillingwise direction:

STRETCH IN RESPONSE TO FORCE Force lb./ in. Percent stretch The stretch recovery of the uncoated fabric has been calculated in a similar manner as previously explained.

In testing the stretchable vinyl coated fabric (FIG- URES 11 and 12), it has been found that it has increased stretch (44 percent) as compared to the uncoated fabric (39.6 percent), and that it Will quickly recover a relatively high percentage of the amounts stretched. For example, the following chart indicates the percentage of stretch of the fabric when various forces are applied in a fillingwise direction:

STRETCH IN RESPONSE TO FORCE Force lb./ in. Percent stretch 5 11.1 10 20.7 15 28.2 20 33.5

. it) The results of the stretch recovery test of the stretchable vinyl coated fabric are listed in the chart below:

Stretch Recovery Inches Percent of Inches re- Percent of per 5 stretch covered stretch recovered A comparison of the stretch recovery characteristics of the stretchable vinyl coated fabric with those of the stretchable uncoated fabric reveals that the vinyl coated fabric quickly recovers a much greater percentage. Also, the filling stretch at break is greater after the vinyl coating is applied (44 compared to 39.6) and the ability to stretch in response to given forces is not substantially reduced, particularly when the higher forces are applied.

The filling toughness of the vinyl coated stretchable fabric has also been determined by multiplying the fillingwise tensile strength (78) by the percent of filling stretch at break (44) and then dividing the product by 2. This calculation results in a filling toughness of 1716 in the coated stretchable fabric.

The uncoated stretchable fabric has a fillingwise tensile strength of 32.4, and the percent of filling stretch at break is 39.6. Thus, the filling toughness of this uncoated fabric is 642. Comparing this figure with the toughness (1716) of the coated fabric, it is apparent that the coated fabric has almost triple the toughness thereof.

In summation, it is apparent that the woven fabrics of this invention exhibit not only an ability to readily stretch and yield under stresses, but after being treated with a coating or wash and wear finish have an enhanced toughness and tear strength over prior art woven fabrics.- Furthermore, these treated fabrics have an increased degree of recovery or'snap back, even at high elongation, and an increased speed of such recovery upon the release of applied stress.

It is evident that these fabric characteristics have been obtained in a most economical manner which contributes materially to the earlier enumerated varied uses thereof.

In the drawings and specification there have been set forth preferred embodiments of the invention and, al-

though specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A method of making a woven stretchable fabric having the characteristics, in the dry state, of substantial stretchability and recoverability comprising the steps of interweaving groups of non-stretchable twisted warp and filling yarns formed of staple fibers to form a woven fabric of predetermined dimensions which has a cover factor of at least eight in both warp and filling directions, treating the fabric to reduce the dimensions in at least one direction corresponding with the woven direction of one group of yarns and to simultaneously crimp the yarns of this group with the reduced fabric being free of wrinkles and the like, the twist multiple of the yarns of this one group being Within the range of 3.5 to 7, with the twist of the yarns of said one group and the interweaving thereof relative to the yarns in the other group permitting suflicientreduction of the fabric and sufficient crimping of the yarns of the one group during said treating to impart stretchability to the reduced fabric so that it will stretch within the range of 15 to 50 percent in the direction of the crimped yarns and appreciably recover therefrom, and subjecting the fabric in unstretched con-.

dition to a suitable stabilizing material with the outward physical appearance of the fabric being unaltered thereby, said stabilizing material serving to normally prevent further reduction of the dimensions of the fabric while permitting the fabric to be stretched within the above-recited range of stretchability, the stabilizing material resiliently maintaining the fabric in non-stretched condition and serving substantially to enhance the speed and amount of recovery of the fabric to non-stretched condition upon the release of any force imparting stretch thereto.

2. A method of making a woven stretchable fabric having the characteristics, in the dry state, of substantial stretchability and recoverability comprising the steps of interweaving groups of cellulosic water swellable twisted warp and filling yarns formed of staple fibers to form a woven fabric of predetermined dimensions which has a cover factor of at least eight in both warp and filling directions, treating the fabric with a caustic soda solution to reduce the dimensions in at least one direction corresponding with the woven direction of one group of yarns and to simultaneously crimp the yarns of this group with the reduced fabric being free of wringles and the like, the twist multiple of the yarns of this one group being within the range of 3.5 to 7, with the twist of the yarns of said one group and the interweaving thereof relative to the yarns in the other group permitting suificient reduction of the fabric and sufiicient crimping of the yarns of the one group during said treating to impart stretchability to the reduced fabric so that it will stretch within the range of 15 to 50 percent in the direction of the crimped yarns and appreciably recover therefrom, and applying to the fabric while in unstretched condition a stabilizing material selected from the group consisting of thermosetting resins and cross-linking reactants for normally preventing further reduction of the dimensions of the fabric while permitting the fabric to be stretched within the above-recited range of stretchability, the stabilizing material resiliently maintaining the fabric in non-stretched condition and serving substantially to enhance the speed and amount of recovery of the fabric from a stretched condition.

3. A method of making a woven stretchable fabric having the characteristics, in the dry state, of substantial stretchability and recoverability comprising the steps of interweaving groups of cellulosic water swellable and shrinkable twisted warp and filling yarns formed of staple fibers to form a woven fabric of predetermined dimensions which has a cover factor of at least eight in both warp and filling directions, treating the fabric with a caustic soda solution to reduce the dimensions in at least the filling direction and to simultaneously crimp the filling yarns in a plane perpendicular to the face of the fabric, the filling yarns having a twist multiple within the range of 3.5 to 7, with the twist of the filling yarns and the interweaving thereof relative to the warp yarns permitting sufiicient reduction of the fabric and sutficient crimping of the filling yarns during said treating to provide stretchability to the reduced fabric so that it will stretch within the range of 15 to 50 percent in the filling direction and appreciably recover therefrom, and subjecting the fabric in unstretched condition to a suitable stabilizing material with the outward physical appearance of the fabric being unaltered thereby, said stabilizing material serving to normally prevent further reduction of the dimensions of the fabric while permitting the fabric to be stretched within the above-recited range of stretchabiiity, the stabilizing material resiliently maintaining the fabric in non-stretched condition and serving substantially to enhance the speed and amount of recovery of the fabric to non-stretched condition upon the release of any force imparting stretch thereto.

4. A method of modifying a woven essentially cellulosic fabric to impart dry state characteristics of substantial stretchability and recoverability thereto, said fabric having groups of warp and filling yarns interwoven with each other and providing a cover factor of at least eight in both warp and filling directions and the twist multiple of one Of the groups of yarns being within the range of 3.5 to 7, said method comprising the steps of treating the fabric to reduce the dimensions in at least one direction corresponding with the woven direction of said one group of yarns and to simultaneously crimp the yarns of this group to impart stretch to the fabric within the range of 15 to 50 percent in the direction of the crimped yarns, and thereafter subjecting the fabric while said one group of yarns is in unstretched crimped condition to a stabilizing treatment without essentially altering the outward appearance of the fabric and to normally prevent further reduction of the dimensions of the fabric while still allowing the fabric to be stretched within its above-recited range of stretchability, the fabric, when in dry state, being resiliently maintained in non-stretched condition by the stabilizing material and having the speed and amount of recovery from a stretched condition substantially enhanced thereby.

5. A method of modifying a woven essentially cellulosic fabric to impart dry state characteristics of substantial stretchability and recoverability thereto, said fabric having groups of warp and filling yarns interwoven with each other and providing a cover factor of at least eight in both warp and filling directions and the twist multiple of one of the groups of yarns being within the range of 3.5 to 7, said method comprising the steps of treating the fabric to reduce the dimensions in at least one direction corresponding with the woven direction of said one group of yarns and to simultaneously crimp the yarns of this group to impart stretch to the fabric within the range of 15 to 50 percent in the direction of the crimped yarns, bleaching the thus treated fabric, and thereafter subjecting the fabric while said one group of yarns is in unstretched crimped condition to a stabilizing treatment without essentially altering the outward appearance of the fabric and to normally revent further reduction of the dimensions of the fabric while still allowing the fabric to be stretched within its above-recited range of stretchability, the fabric, when in dry state, being resiliently maintained in non-stretched condition by the stabilizing material and having the speed and amount of recovery from a stretched condition substantially enhanced thereby.

6. A method of modifying a woven essentially cotton fabric to impart dry state characteristics of substantial stretchability and recoverability thereto, said fabric having groups of warp and filling yarns interwoven with each other and providing a cover factor of at least eight in both warp and filling directions and the twist multiple of the group of filling yarns being within the range of 3.5 to 7, said method comprising the steps of treating the fabric with a caustic soda solution while applying warpwise tension to the fabric and substantially no tension fillingwise to reduce the dimensions of the fabric in the fillingwise direction and to simultaneously crimp the filling yarns to impart stretch to the fabric within the range of 15 to 50 percent in the direction of the crimped filling yarns, and thereafter subjecting the fabric while said group of filling yarns is in unstretched crimped condition to a stabilizing treatment without essentially altering the outward appearance of the fabric and to normally prevent further reduction of the dimensions of the fabric while still allowing the fabric to be stretched within its above-recited range of stretchability, the fabric, when in dry state, being resiliently maintained in non-stretched condition by the stabilizing material and having the speed and amount of recovery from a stretched condition substantially enhanced thereby.

7. A method of modifying a woven essentially cotton fabric to impart dry state characteristics of substantial stretchability and recoverability thereto, said fabric having groups of warp and filling yarns interwoven with each other and providing a cover factor of at least eight in 13 both warp and filling directions and the twist multiple of one of the groups of yarns being within the range of 3.5 to 7, said method comprising the steps of treating the fabric with a caustic soda solution to reduce the dimensions in at least one direction corresponding with the woven direction of said one group of yarns and to simultaneously crimp the yarns of this group to impart stretch to the fabric within the range of 15 to 50 percent in the direction of the crimped yarns, and thereafter subjecting' the fabric while said one group of yarns is in unstre'tcjhed crimped condition to a stabilizing treatment without essentially altering the outward appearance of the fabric and to normally prevent further reduction of the dimensions of the fabric while still allowing the fabric to be stretched within its above-recited range of stretchability, the fabric, when in dry state, being resiliently maintained in non-stretched condition by the stabilizing material and having the speed and amount of recovery from a stretched condition substantially enhanced thereby.

8. A method according to claim 7 wherein the dimensions of the fabric are reduced in a fillingwise direction and the stretchability imparted to the fabric is approximately 30 percent in the fillingwise direction.

9. A method of modifying a woven essentially cellulosic fabric to impart dry state characteristics of substantial jstretchability and recoverability thereto, said fabric having groups of warp and filling yarns interwoven with each other and providing a cover factor of at least eight in both warp and filling directions and the twist multiple of one of the groups of yarns being within the range of 3.5 to 7, said method comprising the steps of treating the fabric with a caustic soda solution to reduce the dimensions in at least one direction corresponding with the woven direction of said one group of yarns and to simultaneously crimp the yarns of this group to impart stretch to the fabric of at least 24 percent at breaking elongation in the direction of the crimped yarns, and thereafter subjecting the fabric while said one group of yarns is'in unstretched crimped condition to a stabilizing treatment to resiliently maintain the fabric in nonstretched condition without essentially altering the outward appearance of the fabric and to normally prevent further reduction of the dimensions of the fabric while still allowing the fabric to be stretched and providing a two minute recovery of enhanced speed and amount and of at least about 75 percent of its elongation when the fabric has been elongated to about one-half of its breaking elongation.

References Cited by the Examiner UNITED STATES PATENTS 1,823,034 9/ 1931 Dworsky et al 2876 1,823,053 9/1931 Lawton 2876 1,885,019 10/1932 Thies 2876 2,404,837 7/ 1946 Goldthwait 2876 2,493,381 1/1950 Balassa 2874 2,524,399 10/1950 Schoene et al. 8-116 2,555,260 5/1951 Walters 28-80 2,573,773 11/1951 Rowe 2880 2,574,029 11/1951 Foster 28-76 2,574,200 11/ 1951 Teague 28--80 2,677,872 5/ 1954 Teague 139-421 2,709,141 5/1955 Burks 8--116.3 X 2,785,947 3/1957 Kess et a1. 8116 2,785,949 3/1957 Kress 8116 2,823,444 2/1958 Davies et a1. 2876 X 2,857,654 10/1958 Sexton 2880 2,906,001 9/ 1959 Stuewer et al. 2876 2,957,746 10/ 1960 Buck et a1 2876 2,995,154 8/1961 Seltzer 139-383 3,001,262 9/1961 Parker 2618.5 3,039,167 6/1962 Land 2876 FOREIGN PATENTS 543,841 7/ 1947 Canada.

571,625 9/ 1945 Great Britain.

752,191 7/ 1956 Great Britain.

OTHER REFERENCES Goldthwait et al.: Special Elastic Properties of Cotton Yarn and Cloth Mercerized Without Tension, Textile Research Journal, vol. XXV, No. 1, January 1955,

References Cited by the Applicant FOREIGN PATENTS 291,473 6/ 1928 Great Britain. 291,474 6/1928 Great Britain. 304,900 1/ 1929 Great Britain. 437,361 10/ 1935 Great Britain. 607,582 9/ 1948 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

I. HERBERT, Assistant Examiner. 

1. A METHOD OF MAKING A WOVEN STRETCHABLE FABRIC HAVING THE CHARACTERISTICS, IN THE DRY STATE, OF SUBSTANTIAL STRETCHABILITY AND RECOVERABILITY COMPRISING THE STEPS OF INTERWEAVING GROUPS OF NON-STRETCHABLE TWISTED WARP AND FILLING YARNS FORMED OF STAPLE FIBERS TO FORM A WOVEN FABRIC OF PREDETERMINED DIMENSIONS WHICH HAS A COVER FACTOR OF AT LEAST EIGHT IN BOTH WARP AND FILLING DIRECTIONS, TREATING THE FABRIC TO REDUCE THE DIMENTSIONS IN AT LEAST ONE DIRECTION CORRESPONDING WITH THE WOVEN DIRECTION OF ONE GROUP OF YARNS AND TO SIMULTANEOUSLY CRIMP THE YARNS OF THIS GROUP WITH THE REDUCED FABRIC BEING FREE OF WRINKLES AND THE LIKE, THE TWIST MULTIPLE OF THE YARNS OF THIS ONE GROUP BEING WITHIN THE RANGE OF 3.5 TO 7, WITH THE TWIST OF THE YARNS OF SAID ONE GROUP AND THE INTERWEAVING THEREOF RELATIVE TO THE YARNS IN THE OTHER GROUP PERMITTING SUFFICIENT REDUCTION OF THE FABRIC AND SUFFICIENT 